The nucleation and growth of interstitial-type dislocation loops were investigated following fusion- or fission-neutron irradiation. The number density of the loops which were formed by either type of irradiation increased linearly with fluence. The average size of the loops also increased. It was concluded that the loops were nucleated directly by defect processes in the cascade zone, and not by reaction among freely migrating point defects in the matrix. When the efficiency of loop formation was assumed to be directly proportional to the energy of the primary knock-on atom that was produced by neutrons, a threshold energy of 20keV and an efficiency of loop formation of 0.4% at this energy was deduced.

Nucleation and Growth of Dislocation Loops in Austenitic Stainless Steels Irradiated with Fission and Fusion Neutrons. Q.Xu, N.Yoshida, T.Yoshiie: Journal of Nuclear Materials, 1998, 258-263, 1730-4